California Department of Transportation


Last Updated: Thursday, February 6, 2014 1:06 PM

Areas Subject to Transportation Conformity Requirements in California

County/Planning Area/Air District
Links exit the Caltrans web site - privacy and other policies may differ

Regional Planning Agency Doing Conformity Analysis Links exit the Caltrans web site - privacy and other policies may differ

Reason for Conformity Requirements (Federal Nonattainment Pollutant, or Attainment with "Section 175A" Maintenance SIP)

Tehama

No MPO — Isolated Rural Area

Caltrans District 2

Tehama County Transportation Commission
  • Ozone
    (Tuscan Butte over 1800 feet elevation only)

Butte

Butte County Association of Governments

  • Carbon Monoxide
    (Chico - Maintenance)
  • Ozone
  • Particulate Matter - PM2.5
    (2006 standard; western part of county - "Chico" area)

Nevada

No MPO — Isolated Rural Area

Caltrans District 3

Nevada County Transportation Commission

  • Ozone (western part of county)

Yuba and Northern Sutter (outside Sacramento ozone area)

Sacramento Area Council of Governments

  • Particulate Matter - PM2.5
    (2006 standard; Sutter and western Yuba Co. - "Marysville/Yuba City" area)
  • Sutter Buttes area (above 2000' elevation) is nonattainment for the 1997 ozone standard until EPA issues final rules governing transition; attains the 2008 standard

Sacramento Metropolitan area: Sacramento; Southern Sutter; Yolo; Solano (E. part); El Dorado, Placer (except Lake Tahoe basin)

Sacramento Area Council of Governments

Metropolitan Transportation Commission
(Solano Co. portion)

  • Carbon Monoxide (Sacramento urbanized area - Maintenance)
  • Ozone
    (includes southern tip of Sutter Co.)
  • Particulate Matter - PM10 (Sacramento County only)
  • Particulate Matter - PM2.5
    (2006 standard; Sacramento and parts of Yolo, Placer, El Dorado, and Solano Counties)

El Dorado, Placer; Nevada Dept. of Environmental Protection (Lake Tahoe basin)

Tahoe Metropolitan Planning Organization

  • Carbon Monoxide (Maintenance)

Bay Area AQMD: Sonoma (S. part), Napa, Solano (W. part), Marin, Contra Costa, Alameda, San Francisco, San Mateo, Santa Clara

Metropolitan Transportation Commission

  • Carbon Monoxide (Maintenance)
  • Ozone
  • Particulate Matter - PM2.5
    (2006 standard)

Calaveras County

No MPO — Isolated Rural Area

Caltrans District 10

Calaveras COG

  • Ozone
  • Note: Amador County was nonattainment for the 1997 ozone standard as part of the "Central Mountain Counties" nonattainment area. For conformity purposes, it is no longer considered nonattainment; for other purposes, it is still nonattainment until EPA issues final rules governing transition.

Mariposa County

No MPO — Isolated Rural Area

Caltrans District 10

Mariposa County LTC (Public Works - Transportation Planning))

  • Ozone
  • Note: Tuolumne County was nonattainment for the 1997 ozone standard as part of the "Southern Mountain Counties" nonattainment area. For conformity purposes, it is no longer considered nonattainment; for other purposes, it is still nonattainment until EPA issues final rules governing transition.

San Joaquin

San Joaquin Council of Governments

  • Carbon Monoxide
    (Stockton - Maintenance)
  • Ozone
  • Particulate Matter - PM10 (Maintenance)
  • Particulate Matter - PM2.5
    (1997 and 2006 standards)

Stanislaus

Stanislaus Council of Governments

  • Carbon Monoxide
    (Modesto - Maintenance)
  • Ozone
  • Particulate Matter - PM10 (Maintenance)
  • Particulate Matter - PM2.5
    (1997 and 2006 standards)

Merced

Merced County Association of Governments

  • Ozone
  • Particulate Matter - PM10 (Maintenance)
  • Particulate Matter - PM2.5
    (1997 and 2006 standards)

Madera

Madera County Transportation Commission

  • Ozone
  • Particulate Matter - PM10 (Maintenance)
  • Particulate Matter - PM2.5
    (1997 and 2006 standards)

Fresno

Fresno Council of Governments

  • Carbon Monoxide
    (Fresno - Maintenance)
  • Ozone
  • Particulate Matter - PM10 (Maintenance)
  • Particulate Matter - PM2.5
    (1997 and 2006 standards)

Kings

Kings County Association of Governments

  • Ozone
  • Particulate Matter - PM10 (Maintenance)
  • Particulate Matter - PM2.5
    (1997 and 2006 standards)

Tulare

Tulare County Association of Governments

  • Ozone
  • Particulate Matter - PM10 (Maintenance)
  • Particulate Matter - PM2.5
    (1997 and 2006 standards)

Kern
(San Joaquin Valley, Mojave Desert, and Indian Wells Valley areas)

Kern County Association of Governments

  • Carbon Monoxide
    (Bakersfield - Maintenance)
  • Ozone
    (except Indian Wells Valley)
  • Particulate Matter - PM10
    (San Joaquin Valley, Maintenance)
  • Particulate Matter - PM10
    (Indian Wells Valley - Maintenance)
  • Particulate Matter - PM10 (Lake Isabella area - Kern County)
  • Particulate Matter - PM2.5
    (San Joaquin Valley; 1997 and 2006 standards)
San Luis Obispo San Luis Obispo Council of Governments
  • Ozone
    (eastern part of county)

Ventura

Southern California Association of Governments

  • Ozone

Los Angeles
(South Coast Air Basin)

Southern California Association of Governments

  • Carbon Monoxide (Maintenance)
  • Ozone
  • Particulate Matter - PM10
  • Particulate Matter - PM2.5
    (1997 and 2006 standards)
  • Nitrogen Dioxide (Maintenance - Annual standard)
  • Lead (Pb) - 2008 Standard (does not affect Transportation Conformity)

Los Angeles
(Antelope Valley)

Southern California Association of Governments

  • Ozone

Orange

Southern California Association of Governments

  • Carbon Monoxide (Maintenance)
  • Ozone
  • Particulate Matter - PM10
  • Particulate Matter - PM2.5
    (1997 and 2006 standards)
  • Nitrogen Dioxide (Maintenance)

San Bernardino
(South Coast Air Basin)

Southern California Association of Governments

  • Carbon Monoxide (Maintenance)
  • Ozone (except lands of the Morongo Band of Mission Indians)
  • Particulate Matter - PM10
  • Particulate Matter - PM2.5
    (1997 and 2006 standards)
  • Nitrogen Dioxide (Maintenance)
Morongo Band of Mission Indians

Morongo Band of Mission Indians

  • Ozone

As part of the South Coast air basin:

  • Carbon Monoxide (Maintenance)
  • Particulate Matter - PM10
  • Particulate Matter - PM2.5
    (1997 and 2006 standard)
  • Nitrogen Dioxide (Maintenance)

San Bernardino
(Trona area)

Southern California Association of Governments

  • Particulate Matter (PM10)

San Bernardino
(Mojave Desert area)

Southern California Association of Governments

  • Ozone (SE Desert Modified portion only)
  • Particulate Matter (PM10)

Riverside
(South Coast Air Basin)

Southern California Association of Governments

Pechanga Band of Luiseño Indians

Pechanga Band of Luiseño Indians

  • Ozone

As part of the South Coast air basin:

  • Carbon Monoxide (Maintenance)
  • Ozone (1997 standard)
  • Particulate Matter - PM10
  • Particulate Matter - PM2.5
    (1997 and 2006 standard)
  • Nitrogen Dioxide (Maintenance)

 

Riverside
(Coachella Valley)

Southern California Association of Governments

Imperial

Southern California Association of Governments

  • Ozone
  • Particulate Matter - PM10 (Imperial Valley area)
  • Particulate Matter - PM2.5
    (2006 standard; "Calexico" area)

San Diego

San Diego Association of Governments

  • Carbon Monoxide (Maintenance)
  • Ozone

Mono (Mono Lake, Mammoth Lakes planning areas)

No MPO — Isolated Rural Areas

Caltrans District 9

Mono County Local Transportation Commission

  • Particulate Matter - PM10
    (Mono Lake and Mammoth Lakes aras only)

Inyo (Owens Valley, Coso Jct. planning areas)

No MPO — Isolated Rural Areas

Caltrans District 9

Inyo County Local Transportation Commission

  • Particulate Matter - PM10
    (Owens Valley and Coso Junction areas only; Coso Junction is maintenance))

Printable (PDF) file

Conformity Areas Table with Regional Conformity Status (PDF file)

Notes:

Tribal considerations: The separate tribal nonattainment areas (the Morongo Band of Mission Indians and the Pechanga Band of Luiseño Indians) are designated individually by the U.S. EPA for ozone (2008 and (for Morongo) 1997 standards) with classifications that differ from the classification of the adjacent South Coast, Coachella Valley, and San Diego areas. For regional conformity purposes, they are currently treated as "donut'" areas and are accounted for in the Southern California Association of Governments (SCAG) regional conformity analysis.

Federal Nonattainment and Maintenance Areas Only: Areas are included in this table only if they are designated by U.S. EPA as nonattainment or attainment (with a Maintenance SIP) under the Federal Clean Air Act (see 40 CFR 81.305  and the U.S. EPA "Green Book”), for pollutants that trigger Transportation Conformity requirements under Federal Clean Air Act Section 176(c) and 40 CFR 93 Subpart A. Many additional areas fail to attain one or more State air quality standards, and the Los Angeles County portion of the South Coast air basin is nonattainment for the 2008 Lead (Pb) NAAQS; however, nonattainment of the State standards and the Lead NAAQS does not trigger transportation conformity requirements under the Federal Clean Air Act.

Other Information Sources:

The latest Air Pollution Control District and Air Quality Management District contact information can be obtained through the California Air Resources Board Links exit the Caltrans web site - privacy and other policies may differ. Links above were current as of February 2013. Air district information can also be obtained at CAPCOA Links exit the Caltrans web site - privacy and other policies may differ.

For the latest contact information related to State and Regional transportation planning agencies, refer to the Caltrans Transportation Planning web site. MPO/RTPA web links were current as of February 2013. MPO and RTPA information can also be obtained at CALCOG Links exit the Caltrans web site - privacy and other policies may differ.

Maps and other materials related to nonattainment area designations in California can be found at the Federal Highway Administration, California Air Resources Board, and at EPA Region 9 (both Links exit the Caltrans web site - privacy and other policies may differ).

More information regarding Transportation Conformity, including links to legislation, regulations, and guidance, can be found at the Federal Highway Administration and EPA conformity web sites (both Links exit the Caltrans web site - privacy and other policies may differ).

Sources:

Federal Highway Administration Links exit the Caltrans web site - privacy and other policies may differ, US Environmental Protection Agency Links exit the Caltrans web site - privacy and other policies may differ, California Air Resources Board Links exit the Caltrans web site - privacy and other policies may differ, Metropolitan Planning Organizations shown in table Links exit the Caltrans web site - privacy and other policies may differ, Caltrans Division of Transportation Planning

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